Thermal protection fabric

ABSTRACT

The invention concerns a fabric comprising a weave of warp yarns in one direction and of weft yarns in the perpendicular direction. Said fabric comprises, in one direction, yarns consisting of alternating continuous filaments and spun yarns, and in the other direction, yarns produced from spun yarns, the various continuous filaments being produced in flame retardant and non-fusible materials.

[0001] The subject of the present invention is a woven thermal protection fabric, especially a woven fabric that can be used for producing garments worn by firefighters.

[0002] Textile protective jackets for firefighters are obtained by assembling several layers of material with the aim of providing a high level of protection in accordance with standards, especially the EN469 standard in force in Europe.

[0003] A textile protective jacket generally comprises an external layer consisting of a woven fabric made of an aramid or the equivalent, an impermeable barrier laminated to a non-inflammable felt, an insulation system, consisting of a knit or a felt made of an aramid or the equivalent, and an internal lining.

[0004] When such a type of jacket is used, there are a number of drawbacks.

[0005] Such a jacket is very heavy and poses ergonomic and ease-of-movement problems to the wearer because of the stacking of several layers.

[0006] Finally, such a jacket is difficult to clean and there may be problems with its appearance after washing.

[0007] Document U.S. Pat. No. 5,299,602 discloses an external woven fabric for a firefighter's jacket, the warp of which comprises continuous filaments of meta-aramid (known by the trademark Nomex) alternating with multifilaments of para-aramid, such as that known under the trademark Kevlar, and a weft comprising Nomex-type meta-aramid staple fiber yarns alternating with Kevlar-type para-aramid multifilaments, the whole assembly being linked together by a crossed-type weave.

[0008] The use of Kevlar-type para-aramid multifilaments as warp, as one yarn in two, has drawbacks for the following reasons:

[0009] it is known and has been demonstrated that para-aramid multifilaments are very sensitive to hydrolysis. They have a poor resistance to washing conditions in an aqueous medium—they therefore rapidly lose their mechanical performance and become more sensitive to abrasion, therefore resulting in fibrillation, which is a deterioration of the yarn resulting in the appearance of a whitish contamination on the fabric;

[0010] para-aramid multifilaments are sensitive to ultraviolet radiation and to part of the visible spectrum, for wavelengths of between 300 and 450 nm, in the presence of which they lose their original mechanical properties quite quickly; and

[0011] from the economic standpoint, the use of para-aramid multifilaments incurs a substantial cost burden when producing this fabric compared with the use of another type of material.

[0012] It is an object of the invention to provide a woven thermal protection fabric which possesses good thermal protection and mechanical protection properties, has a good resistance to washing and has a good surface appearance after washing, has a good resistance to radiation, such as ultraviolet radiation, and offers a satin or shiny surface appearance making it possible for the wearer of a garment made up from such a fabric to be identified in poor visibility conditions, especially when working in a smoke-filled area.

[0013] For this purpose, the woven thermal protection fabric to which the invention relates, comprising a weave of warp yarns in one direction and of weft yarns in the perpendicular direction, is characterized in that it comprises, in one direction, yarns consisting of an alternation of continuous filaments and of staple fiber yarns and, in the other direction, yarns made from staple fiber yarns, the various continuous filaments and staple fiber yarns being made of non-inflammable and non-melting materials.

[0014] According to an option:

[0015] the continuous filaments are made of a meta-aramid, such as that known under the trademark Nomex;

[0016] the staple fiber yarns combined alternately with the continuous filaments are made of a meta-aramid, such as that known under the trademark Nomex; and

[0017] the yarns consisting of staple fiber yarns in the other direction comprise fibers of a meta-aramid, such as that known under the trademark Nomex, and fibers of a para-aramid, such as that known under the trademark Kevlar.

[0018] The combination of continuous filaments and staple fiber yarns in one direction of the woven fabric with staple fiber yarns in the other direction procures very good thermal protection, while still ensuring that the woven fabric has excellent mechanical properties.

[0019] The very good mechanical performance of the constituent yarns of this woven fabric makes it possible to produce a fabric possessing balanced mechanical properties.

[0020] According to one embodiment of this woven fabric, the para-aramid fibers are arranged as core and the meta-aramid fibers are arranged as cover. Advantageously, the yarns are produced from staple fiber yarns comprising approximately ⅓ of para-aramid fibers and ⅔ of meta-aramid fibers.

[0021] This arrangement is advantageous insofar as the para-aramid fibers give the fabric high mechanical properties, without any risk of the fibrillation problem, nor any loss of strength, since the para-aramid fibers are protected by the meta-aramid fibers placed as cover.

[0022] According to one advantageous embodiment of this woven fabric, the various yarns in the two directions are combined so as to form a double-sided complex satin-type weave, such that the external face of the fabric is essentially composed of continuous filaments and the internal face is essentially composed of staple fiber yarns.

[0023] The presence of continuous filaments on the external face of the woven fabric makes it possible to obtain a closed, smooth and uniform surface since the constituent filaments of each of the yarns have a tendency to spread out and occupy the maximum amount of surface available, thereby resulting in the formation of a barrier to the radiant heat flux.

[0024] The surface thus formed has a very shiny appearance compared with that obtained with staple fiber yarns, this effect resulting in excellent reflection at the radiant heat. Furthermore, this shiny surface allows the person wearing the garment to be easily identifiable in a smoke or fire situation or in the dark, since the continuous filaments reflect the light, unlike the conventional outer layers that remain mat.

[0025] In addition, this smooth outer layer gives the wearer greater ease of movement by reducing the friction of the various parts of the Jacket when one part moves relative to another.

[0026] Finally, by virtue of the presence of continuous filaments on the outside of the woven fabric, the garment is easier to clean since, during use, the outer layer does not form a catching surface, any dust and debris not sticking to this surface.

[0027] Insofar as a substantial proportion of the staple fiber yarns appear predominantly on the rear face of the fabric, they contribute to the resistance to flame propagation.

[0028] Advantageously, the staple fiber yarns, dispersed among the continuous filaments in one direction, are linked with the yarns of the other direction on the rear face of the fabric and they have a higher linear density than the continuous filaments. Insofar as the staple fiber yarns present on the rear face of the fabric possess a higher linear density than the continuous filaments, they provide a relief effect with the formation of additional thicknesses which, once in contact with the second layer of the textile complex, define an air space which contributes to the thermal insulation of the garment.

[0029] In order to give the fabric the most closed possible appearance on its outer face, the yarns, in one direction, consist of an alternation of continuous filaments and of staple fiber yarns in proportions of 5 to 1.

[0030] Electrostatic properties may be obtained in this type of woven fabric by combining dissipating or electrostatic yarns or fibers in one or other of the directions.

[0031] Given below, as a non-limiting example, is one embodiment of a woven fabric according to the invention.

[0032] This woven fabric comprises warp yarns consisting of continuous filaments of a meta-aramid, of Nomex type, of 220 dtex linear density and of staple fiber yarns of a meta-aramid, of Nomex type, of 60/2 Nm linear density in the proportion of 5 to 1, and weft yarns consisting of staple fiber yarns of 55/2 Nm linear density that are produced using the core yarn technique, composed of about 33% of Kevlar-type para-aramid fibers as core and 67% of Nomex-type meta-aramid fibers as cover, the weave being of the satin type with filaments on the front face, while the staple fiber yarns appear predominantly on the back face where they are linked with the warp yarns to form a reinforcing mesh, the fabric optionally undergoing a waterproofing-type finishing treatment making it possible to provide water-repellency characteristics. To form a three-layer complex that can be used for producing a protective garment, for example for firefighters, this woven fabric may be combined with an intermediate layer consisting of a membrane laminated to a felt and an inner layer consisting of a lining.

[0033] An assembly, as defined above, was tested and shows excellent thermal performance characteristics compared with the known complexes comprising four layers with an external layer made 100% of aramid or equivalent. It is therefore possible to save on one layer in the assembly, while ensuring excellent protection of the wearer, and increasing his comfort. Furthermore, the satin effect makes it easier to clean the garment and contributes to being able to identify and locate the wearer in poor external environmental conditions, such as in smoke or in the dark.

[0034] As goes without saying, the invention is not limited to the single embodiment of this woven fabric described above by Stay of example, rather it encompasses any variant that remains within the scope of the claims. Thus, in particular, other materials having a non-inflammable and non-melting character can be used, such as those belonging to the families of aramids, polyimides, polybenzimidazoles and polybenzazoles. 

1. A woven thermal protection fabric comprising a weave of warp yarns in one direction and of weft yarns in the perpendicular direction, characterized in that it comprises, in one direction, yarns consisting of an alternation of continuous filaments and of staple fiber yarns and, in the other direction, yarns made from staple fiber yarns, the various continuous filaments and staple fiber yarns being made of non-inflammable and non-melting materials.
 2. The woven fabric as claimed in claim 1, characterized in that the continuous filaments are made of a meta-aramid, such as that known under the trademark Nomex.
 3. The woven fabric as claimed in either of claims 1 and 2, characterized in that the staple fiber yarns combined alternately with the continuous filaments are made of a meta-aramid, such as that known under the trademark Nomex.
 4. The woven fabric as claimed in one of claims 1 to 3, characterized in that the yarns consisting of staple fiber yarns in the other direction comprise fibers of a meta-aramid, such as that known under the trademark Nomex, and fibers of a para-aramid, such as that known under the trademark Kevlar.
 5. The woven fabric as claimed in claim 4, characterized in that the para-aramid fibers are arranged as core and the meta-aramid fibers are arranged as cover.
 6. The woven fabric as claimed in one of claims 1 to 5, characterized in that the various yarns in the two directions are combined so as to form a double-sided complex satin-type weave, such that the external face of the fabric is essentially composed of continuous filaments and the internal face is essentially composed of staple fiber yarns.
 7. The woven fabric as claimed in claim 6, characterized in that the staple fiber yarns, dispersed among the continuous filaments in one direction, are linked with the yarns of the other direction on the rear face of the fabric and in that they have a higher linear density than the continuous filaments.
 8. The woven fabric as claimed in one of claims 1 to 7, characterized in that the yarns, in one direction, consist of an alternation of continuous filaments and of staple fiber yarns in proportions of 5 to
 1. 9. The woven fabric as claimed in claim 4, characterized in that the yarns, in one direction, are produced from staple fiber yarns comprising approximately ⅓ of para-aramid fibers and ⅔ of meta-aramid fibers.
 10. The woven fabric as claimed in all of claims 1 to 9, characterized in that it comprises warp yarns consisting of continuous filaments of a meta-aramid, of Nomex type, of 220 dtex linear density and of staple fiber yarns of a meta-aramid, of Nomex type, of 60/2 Nm linear density in the proportion of 5 to 1, and weft yarns consisting of staple fiber yarns of 55/2 Nm linear density that are produced using the core yarn technique, composed of about 33% of Kevlar-type para-aramid fibers as core and 67% of Nomex-type meta-aramid fibers as cover, the weave being of the satin type with filaments on the front face, while the staple fiber yarns appear predominantly on the back face where they are linked with the warp yarns to form a reinforcing mesh, the fabric optionally undergoing a waterproofing-type finishing treatment making it possible to provide water-repellency characteristics. 